Modern automobiles are typically equipped with multiple independent electronic components. For instance, most modern automobiles have an electronic engine control system, a computerized antilock braking system (ABS), a vehicle safety system, a lighting control system, a climate control subsystem, and a sound system. The engine control system usually employs an electronic controller to in maximize fuel economy and minimize harmful emissions. The antilock braking system uses electronic sensors and microprocessors to slow an automobile at an optimal rate while preventing skidding. The vehicle safety system has a crash response controller that is triggered during a crash to deploy one or more airbags.
Some recent automobile models are equipped with a navigation system that employs a global positioning system (GPS) receiver to receive positioning signals from a satellite network. The navigation system computes coordinates that locate the vehicle over the surface of the earth with regard to longitude, latitude, and altitude. Cellular communication systems have also been introduced into automobiles to enable the driver or occupant to transact telephone calls from their vehicle. Most late model automobiles are also constructed with a diagnostic system that analyzes the performance of the automobile engine, air and heating system, and other components (1996 or later for OBD II, 1993 or later for OBD I).
While these various electronic components have proven useful, there is a drawback in that all of them are entirely separate and independent from one another. Generally, these subsystems are supplied by different manufacturers.
These disparate components often employ proprietary, dedicated processors or ASICs (application specific integrated circuits) that have different system architectures and execute incompatible proprietary software. The components have limited or no communications with one another.
Some strides have been made to integrate the components. Typically, the proposals call for each of the distributed components to be connected to a data bus, such as a CAN (Controller Area Network) protocol bus. Designers have theorized different multiplexing protocols and token passing protocols to facilitate communication over the bus. For more information on these proposals, the reader is directed to the following articles which appear in a publication from the Society of Automotive Engineers (SAE): Inoue et al., "Multiplex Systems for Automotive Integrated Control," Multiplex Technology Applications in Vehicle Electrical Systems, SP-954, No. 930002, copyright 1993; Azuma et al., "Development of a Class C Multiplex Control IC," Multiplex Technology Applications in Vehicle Electrical Systems, SP-954, No. 930003, copyright 1993; Mathony et al. "Network Architecture for CAN," Multiplex Technology Applications in Vehicle Electrical Systems, SP-954, No. 930004, copyright 1993; Szydolowski, "A Gateway for CAN Specification 2.0 Non-Passive Devices," Multiplex Technology Applications in Vehicle Electrical Systems, SP-954, No. 930005, copyright 1993; al., "Open Systems and Interfaces for Distributed Electronics in Cars (OSEK)," Automotive Multiplexing Technology, SP-1070, No. 950291, copyright 1995; and Emaus, "Aspects and Issues of Multiple Vehicle Networks," Automotive Multiplexing Technology, SP-1070, No. 950293, copyright 1995.
While there has been some progress at interconnecting electronic components in a distributed system via a communication link, there is no commonly accepted standard for the main vehicle system bus and bus interface. Additionally, even in the distributed architecture, the electronic components are individually vulnerable to unrecoverable failure. When a component experiences an electronics failure, such as a failed controller, the component is either rendered entirely useless or reduced to a safe, but otherwise sub-optimally performing unit.
The inventors have developed a fault-resilient system which solves these problems.